JP4333359B2 - Geothermal steel pipe pile - Google Patents

Description

  The present invention relates to an efficient screw-in type geothermal steel pipe pile using, for example, a steel pipe pile that is a foundation pile of a structure as a geothermal exchanger.

  For example, the use of foundation piles of structures as geothermal exchangers has been proposed in the past, and has many achievements overseas. Since the underground temperature is stable throughout the year, it can be used as a heat source in summer and as a heat source in winter.

As a technique of this type, there is a heat exchange pile in which a spiral heat exchange pipe in which a forward pipe and a return pipe in which a heat medium flows are alternately wound is embedded in a concrete hollow pile body.
According to this heat exchange pile, since the heat exchange pipe in which the forward pipe and the return pipe in which the heat medium flows are alternately wound is embedded in the main body, the heat absorption area is increased and the geothermal absorption efficiency is improved ( For example, see Patent Document 1).

In addition, when a tubular pile for civil engineering construction with an open end is installed and constructed by advancing from the ground to the ground, a ground heat exchanger that allows a heat medium to pass through the cavity inside the pile is installed at the top of the pile. A method of manufacturing a ground heat exchange facility has been proposed in which the pile is filled with solid and solid fillers after being inserted from the section.
According to this method, it becomes unnecessary to excavate a dedicated vertical shaft for installing the ground heat exchanger in the ground, and the installation cost of the ground heat exchange equipment can be reduced as compared with the conventional technology (for example, Patent Document 2). reference).

Furthermore, the rotary press-fit steel pipe pile is rotary press-fitted into the ground, and water can be stored by sealing with a bottom cover provided at the tip or midway of the rotary press-fit steel pipe pile. Underground temperature stratified thermal storage tanks using rotary press-fit piles with intake pipes have been proposed.
Since this water tank can be buried in the ground by rotationally press-fitting a rotary press-fit steel pipe pile, there is no need for excavation, construction cost is reduced, and high support force is obtained as a foundation pile (for example, patent document) 3).

JP-A-11-336008 JP 2003-148079 A JP 2003-247792 A

Since the heat exchange pile of patent document 1 installs a heat exchange pipe in the inside of a concrete hollow pile, and performs heat transfer from the ground via concrete, thermal efficiency is bad compared with the case where it absorbs heat directly from the ground. In addition, because it is a concrete pile, there is a problem in its disposal due to soil discharge during construction.
Moreover, since the tip pile part of the tubular pile of patent document 2 is opened, since earth and sand enter in a pipe | tube in most grounds, the process is troublesome. Moreover, since a geothermal heat exchanger must be installed after pile construction, installation is difficult in the case of a small-diameter tubular pile. Furthermore, air is used as a heat exchange medium, but since the specific heat is lower than that of water or the like, the efficiency as a heat medium is poor.

  In Patent Document 3, the water injection pipe and the water intake pipe are installed in the water tank of the rotary press-fit steel pipe pile at the same time as the pile construction, and can be used as a foundation pile after the construction, but water must be filled in the water tank. It is difficult to replace water during maintenance. In addition, a rotary press-fit steel pipe pile using a normal steel pipe is not economical because a steel pipe with a large plate thickness must be used to withstand external forces such as torque acting during construction.

  The present invention has been made to solve the above-mentioned problems, and by installing a heat exchange pipe constituting the geothermal exchanger on the outer peripheral surface of the pile body, the thermal efficiency is improved and the external pressure acting on the pile body is increased. The purpose of the present invention is to provide a screw-in type geothermal steel pipe pile that can serve as a reinforcement.

Geothermal steel pipe pile according to the present invention, the wing is attached to the distal end or near a steel pipe, having a screw-in steel pipe piles are embedded intruded into the ground by applying a rotational force to the steel pipe, the A heat exchange pipe is spirally wound around the outer peripheral surface of the screwed steel pipe pile substantially corresponding to the inclination and pitch of the blade .

Further, the geothermal steel pipe pile according to the present invention has a screw-type steel pipe pile in which a blade is attached at or near the tip of the steel pipe and is embedded in the ground by applying a rotational force to the steel pipe. A spiral multistage blade is provided on the outer peripheral surface of the screwed steel pipe pile, and a heat exchange pipe is installed along the root of the multistage blade.

A protective cover was provided on the heat exchange pipe.
The pile head of the screw-in type steel pipe pile was expanded in diameter, and the pipe for heat exchange was wound around the outer peripheral surface of the expanded diameter part.

In the geothermal steel pipe pile according to the present invention, the heat exchanging pipe is wound around the outer peripheral surface of the screw-in type steel pipe pile, and the heat exchange directly with the ground can be performed efficiently.
Moreover, since the protective cover is provided on the heat exchange pipe, the protective cover serves to reinforce the pile body, so that deformation and breakage of the pile body can be prevented during construction, and an economical design can be performed. .

[Embodiment 1]
FIG. 1 is a schematic diagram of a geothermal steel pipe pile according to Embodiment 1 of the present invention.
In the figure, reference numeral 2 denotes a screwed steel pipe pile (hereinafter simply referred to as a steel pipe pile), which is attached to a steel pipe 3 (hereinafter sometimes referred to as a pile body) and a tip of the pile body 3 so as to be inclined or spiral. The tip wing 4 is made up of. In addition, the case where the front-end opening part of the pile 3 is obstruct | occluded with the front-end | tip wing | blade 4 is shown in the figure. 10 is made of steel, for example, and is a heat exchange pipe that is wound around the outer peripheral surface of the pile body 3 and filled with a heat medium (for example, a fluid having a good heat exchange rate such as water) and flows. The geothermal steel pipe pile 1 is comprised.

  In the drawing, the tip wing 4 constituting the steel pipe pile 2 is provided with two attachment portions by cutting off the tip portion of the pile body 3 in a substantially letter shape, and having a larger diameter than the outer diameter of the pile body 3 (for example, A steel disk of about twice the outer diameter of the pile body 3 is divided into two to form a semicircular blade plate, and this blade plate is attached to the pile body 3 by covering the tip opening and welding. Although it is shown that it is formed by tilting, for example, a blade plate or a spiral plate divided from a donut-shaped steel plate is attached to the outer periphery near the tip of the pile body, and the tip opening of the pile body is opened as it is However, in the present invention, the shape and structure of the tip wing 4, the attachment position, and the presence or absence of opening and closing of the tip opening of the pile body are not particularly limited. What is necessary is just to be able to satisfy the workability and the vertical bearing capacity characteristics.

  The heat exchange pipe 10 descends substantially vertically along the outer peripheral surface of the pile body 3 from the pile head, and is spirally wound around the outer peripheral surface of the pile body 3 at a predetermined interval from the middle toward the lower part. It is turned up at the lower part and spirally wound around the outer peripheral surface of the pile body 3 in the upward direction between the above intervals, and then raised almost vertically along the outer peripheral surface of the pile body 3. . The heat exchange pipe 10 is completely bonded and fixed to the outer peripheral surface of the pile body 3 by welding or the like. Both end portions 10a and 10b of the heat exchange pipe 10 are pulled out from the pile head and connected to an air conditioner (both not shown) via a pump.

  The heat exchanging pipe 10 is penetrated into the ground while rotating integrally with the steel pipe pile 2 in construction. In this case, the inclination of attachment of the heat exchange pipe 10 to the pile body 3 is made to substantially coincide with the inclination of the tip wing 4, and the pitch is set to the pitch of the tip wing 4 (step per rotation of the pile body 3). If the penetration of the pile body 3 enters according to the pitch of the tip wing 4 at the time of construction, a large external force does not act on the heat exchange pipe 10. However, in the ground having a certain degree of hardness other than the soft ground, the steel pipe pile 2 rarely penetrates according to the pitch of the tip wing 4, so that it is inevitable that some external force acts on the heat exchange pipe 10. it is conceivable that. For this reason, in order to prevent the heat exchange pipe 10 from being deformed or damaged, it is desirable to reliably join the heat exchange pipe 10 having high rigidity to the pile body 3.

  In general, it is considered that the underground temperature is substantially constant if it is about 6 m or more deeper than the ground surface, and the section from the ground surface to the depth of about 6 m is considered not to have very good heat exchange efficiency. Therefore, it is desirable to wind the heat exchange pipe 10 around the outer peripheral surface of the pile body 3 at a position deeper than the ground surface by about 6 m or more. In the section from the ground surface to the depth of about 6 m, the heat exchange pipe 10 is connected to the pile body 3. Even if it is arranged vertically along the outer peripheral surface, it hardly affects the heat exchange efficiency.

  The geothermal steel pipe pile 1 configured as described above is connected to a construction machine having a pile head on the ground, rotated and driven by the tip wing 4 while excavating and softening the ground near the tip of the pile. It penetrates into the ground by four wood screw actions and is buried at a predetermined depth. At this time, the spirally wound heat exchange pipe 10 serves as a rib, contributes to the penetration propulsion force of the steel pipe pile 2, and acts passively when the surrounding earth and sand are discharged to the side of the pile body 3. It plays the role of reinforcing the pile 3 against earth pressure. In addition, the pile body 3 has an effect as a reinforcement against torsional buckling due to torque, pushing force, pulling force, etc. during rotation, and further contributes to improvement of peripheral frictional force due to the protrusion of the heat exchange pipe 10. .

The heat exchange pipe 10 provided on the outer peripheral surface of the steel pipe pile 2 buried in the ground is filled with a heat medium, and this heat medium flows (circulates) in the heat exchange pipe 10 from one end 10a to the other end 10b. ) And heat exchange with geothermal.
In this Embodiment, since the pipe 10 for heat exchange provided in the outer peripheral surface of the pile body 3 is directly contacting with the ground, the geothermal utilization steel pipe pile 1 with high heat dissipation and heat absorption efficiency can be obtained. Moreover, since the pipe 10 for heat exchange can be previously installed in the pile body 3 at a factory etc., the effort after construction can be saved (the same applies to the following embodiments).

[Embodiment 2]
FIG. 2 is a schematic diagram of a geothermal steel pipe pile according to Embodiment 2 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In this embodiment, a geothermal steel pipe pile 1 is joined to a footing 20 that is the foundation of a building.

A foundation pile usually has a large bending moment due to a horizontal force in the vicinity of the pile head. Although this bending moment depends on the pile diameter and external force, a normal pile is very small below a certain depth (for example, 10 m), so that only the vertical force needs to be considered as the force acting on the pile body.
So, in this Embodiment, when using this geothermal utilization steel pipe pile 1 as a foundation, it is below the section (deeper than about 10 m from the ground surface) where the heat exchange pipe 10 cannot ignore the effect of this bending moment. Provided in the pile body 3 to prevent deformation and breakage due to bending moment, above both ends 10a, 10b of the heat exchange pipe 10 are drawn into the pile body and taken out from the pile head to the outside Is. As described above, since the heat exchange efficiency is low in the section from the ground surface to a depth of about 6 m, even if the upper part of the heat exchange pipe 10 is drawn into the pile body, the heat exchange efficiency is not affected.

  In the present embodiment, in the case of the steel pipe pile 2 with the tip opening closed, the earth and sand excavated by the tip wing 4 does not enter the pile body, so there is no problem even if the heat exchange pipe 10 is drawn into the pile body. Even in the case of the steel pipe pile 2 with the opening at the tip, there is no problem because the earth and sand hardly penetrates to the vicinity of the pile head, but if there is a possibility that the earth and sand may rise to the vicinity of the pile head What is necessary is to provide a lid or the like in the pile body to suppress the rise of earth and sand.

  Also in the present embodiment, substantially the same effect can be obtained by the same operation as in the first embodiment. In addition, this Embodiment (drawing the upper part of the pipe 10 for heat exchange in a pile body) can also be implemented also in Embodiment 1 and other embodiments described below.

[Embodiment 3]
FIG. 3 is a schematic diagram of a geothermal steel pipe pile according to Embodiment 3 of the present invention and an explanatory diagram of the main part. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the present embodiment, a steel material such as a section steel (in the figure, an angle steel is shown) is provided on the outer peripheral surface of the heat exchange pipe 10 of the geothermal steel pipe pile 1 according to the first and second embodiments. Thus, a protective cover 11 is provided.

  This protective cover 11 is made of steel having a relatively large rigidity, covers the heat exchange pipe 10 spirally wound around the outer peripheral surface of the pile body 3, and is joined to the outer peripheral surface of the pile body 3 by welding. Thus, it is desirable to install the tip blade 4 at an angle in accordance with the pitch of the tip wings 4, but a pitch that is coarser than this can be used.

According to the present embodiment, substantially the same operation and effect as in the case of the first embodiment can be obtained. However, since the protective cover 11 is provided so as to cover the heat exchange pipe 10, the heat exchange pipe 10 is There is no risk of deformation or breakage due to earth pressure or the like, and for this reason, the heat exchange pipe 10 having relatively low rigidity can be used.
Moreover, by providing the protective cover 11, the propulsive force of the pile body peripheral surface portion is increased, and the penetration performance of the steel pipe pile 2 is improved as compared with the case where only the tip wing 4 is provided.
Furthermore, since the protective cover 11 serves to reinforce the pile body 3, it can counteract the passive earth pressure that acts when the earth and sand are discharged to the side during construction. It can also handle torsional buckling due to external forces such as torque, pushing force and pulling force. In addition, a large peripheral frictional force can be obtained by the protective cover 11 when sharing.

  Although not shown, a cylindrical outer tube is disposed so as to cover at least the spirally wound portion of the heat exchange pipe 10 provided on the outer peripheral surface of the pile body, and this portion is double tube. The heat exchange pipe 10 may be protected from external force or the like by using a structure.

[Embodiment 4]
FIG. 4 is a schematic view of a geothermal steel pipe pile according to Embodiment 4 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the present embodiment, a plurality of spiral wings 12 are provided on the outer peripheral surface of the pile body 3, and a heat exchange pipe 10 is installed along the top surface of the root of the spiral wing 12. In this case, the heat exchange pipe 10 is protected from external force.

The spiral blade 12 may have an outer diameter substantially equal to or larger than that of the tip blade 4 of the first embodiment. However, considering the protection of the heat exchange pipe 10, the tip blade 4 can be used. It may be of a smaller diameter and is attached to the outer peripheral surface of the steel pipe 3 by welding or the like with the same inclination and the same pitch as the tip blade 4.
Then, the heat exchanging pipe 10 is wound around the outer peripheral surface of the pile body 3 along the upper surface of the root portion of the spiral blade 12, and is fixed to the pile body 3 or the spiral blade 12 or both by welding or an adhesive. Is done. At this time, both ends of the heat exchange pipe 10 may be taken out along the outer peripheral surface of the pile body 3, or may be drawn into the pile body 3 and taken out to the outside.

  According to the present embodiment, substantially the same effect as that of the third embodiment can be obtained. In addition, since it penetrates into the ground by the wood screw action of both the tip wing 4 and the spiral wing 12, the propulsive force is increased, but a larger torque is required for the provision of the spiral wing 12. Moreover, since the spiral wing 12 is screw-shaped, there is a possibility that the earth and sand may be pushed upward when penetrating into the ground. Ingenuity is necessary. Note that the tip wing 12 may be omitted, and the steel pipe pile 2 may be penetrated into the ground with only the spiral wing.

[Embodiment 5]
FIG. 5 is a schematic view of a geothermal steel pipe pile according to Embodiment 5 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the present embodiment, a lower pile 3a made of a steel pipe having a tip wing 4 attached to the tip end, and an upper pile 3b made of a steel pipe having a larger diameter than the upper pile 3b are attached to the upper end of the lower pile 3a. A steel pipe pile 2 is configured by connecting via a circular steel plate 5 having an outer diameter substantially equal to the diameter, and a heat exchange pipe 10 is wound around the outer peripheral surface of the upper pile 3b.

  Since it is desirable that the heat exchange pipe 10 is wound around the outer peripheral surface of the upper pile 3b below the section where the effect of the bending moment caused by the horizontal force cannot be ignored, the length of the upper pile 3b is, for example, 10 m or more. The heat exchange pipe 10 is provided at a position deeper than 10 m. And it is desirable to take in the both ends of the pipe 10 for heat exchange in the upper pile 3b about 6m or 5D (D is the outer diameter of the upper pile 3b) downward from the pile head.

According to the present embodiment, a large tip support force can be obtained by the large tip wing 4 and the horizontal force can be resisted by a large pile section of the upper pile 3b (head expansion), so that it balances against the external force. A good geothermal steel pipe pile 1 can be obtained.
Furthermore, since the upper pile 3b has a large diameter, the long heat exchange pipe 10 wound around the outer circumferential surface of the upper pile 3b dissipates heat compared to a normal geothermal steel pipe pile (for example, the geothermal steel pipe pile according to the first embodiment). An endothermic effect can be obtained.

FIG. 6 is a schematic diagram showing another example of the present embodiment.
6A shows a lower pile 3a and an upper pile 3b having a larger diameter than that of the upper pile 3b and a blade plate obtained by dividing a circular steel plate or donut-like steel plate having a diameter larger than that of the upper pile 3b and the tip blade 4, or a spiral blade. The other components are the same as in the case of FIG. 5.
In this example, substantially the same effect as in the case of FIG. 5 can be obtained, but further, since the joint blade 6 having a diameter larger than that of the tip blade 4 is provided and penetrated into the ground by both wood screw actions, a larger propulsive force is obtained. And the ground support force can be obtained.

Moreover, FIG.6 (b) connects and integrates the lower pile 3a and the upper pile 3b larger diameter than this by the taper pipe 7, Other structures are the same as that of the case of FIG.
In this example, substantially the same effect as in the case of FIG. 5 can be obtained, but furthermore, since the lower pile 3a and the upper pile 3b are connected by the taper pipe 7 that gradually expands in diameter, the penetration into the ground can be performed smoothly. Can do. In addition, the connection of the lower pile 3a and the upper pile 3b in this Embodiment is not limited to said example, You may use another means.
In order to increase the propulsive force, the pile 3a, the upper pile 3b, or the tapered tube 7 may be provided with plate-like or spiral wings.

Next, an example of the present invention will be described with reference to the geothermal steel pipe pile according to the first embodiment.
The steel pipe 3 constituting the screw-in type steel pipe pile 2 has an outer diameter of 1000 mm, a plate thickness of 14 mm, and a length of 30 m. A blade blade obtained by dividing a circular steel plate having a thickness of 60 mm into two parts is attached to be inclined to provide a tip blade 4.

  The heat exchanging pipe 10 is a steel pipe having an outer diameter of 40 mm and a wall thickness of 4 mm. One end is held on the pile head and lowered substantially vertically along the outer peripheral surface of the steel pipe 3, and is lowered 10 m from the pile head. In the meantime, in accordance with the inclination and pitch of the tip wing 4, it is spirally wound downward along the outer peripheral surface of the steel pipe 3 (hereinafter, this portion is referred to as the forward path side), and when it is wound 40 times, it is folded back to the forward path side. Winding upward along the pipes. Then, the winding is stopped 10 m below the pile head, and the winding is lifted almost vertically along the outer peripheral surface of the steel pipe 3 (hereinafter, this portion is referred to as the return path side), and the ends of the pipes on the forward path side and the return path side are externally connected. The steel pipe pile 1 using geothermal heat was configured by temporarily connecting it with a connecting tool.

In this state, the pile head of the geothermal steel pipe pile 1 is connected to a construction machine provided on the ground, the pile body is driven to rotate and penetrates into the ground by the wood screw action of the tip wing 4 and reaches a predetermined depth. When it was done, the construction machine was removed. At this time, the earth and sand in the vicinity of the tip of the steel pipe 3 is excavated and softened by the tip wing 4, moved to the side of the steel pipe 3 and compressed.
At the time of construction, a heat exchange pipe 10 is provided on the outer peripheral surface of the steel pipe 3, but since this heat exchange pipe 10 is wound in a spiral shape, it contributes to the promotion of the steel pipe pile 2, so that it is used for heat exchange. The threaded steel pipe pile having the same structure without the pipe 10 was able to be constructed with substantially the same torque and substantially the same time.

  Next, the end portions on the forward path side and the return path side of the heat exchange pipe 10 were connected via a pump (not shown), and the heat exchange pipe 10 was filled with water as a heat medium. Then, when the water in the heat exchange pipe 10 was circulated by the pump, the water at 25 ° C. initially became 15 ° C. after 20 minutes, and this water temperature was maintained stably thereafter.

  The steel pipe pile 1 using geothermal heat according to the present invention can implement a case where a heat exchanging pipe 10 as a general geothermal exchange system is installed in the ground, and also serves as a foundation pile of a building. It can also be implemented in the system.

It is a schematic diagram of the geothermal utilization steel pipe pile which concerns on Embodiment 1 of this invention. It is a schematic diagram of the geothermal utilization steel pipe pile which concerns on Embodiment 2 of this invention. It is the schematic diagram of the geothermal utilization steel pipe pile which concerns on Embodiment 3 of this invention, and explanatory drawing of the principal part. It is a schematic diagram of the geothermal utilization steel pipe pile which concerns on Embodiment 4 of this invention. It is a schematic diagram of the geothermal utilization steel pipe pile which concerns on Embodiment 5 of this invention. FIG. 20 is a schematic diagram of another example of the fifth embodiment.

Explanation of symbols

1 steel pipe pile using geothermal heat, 2 screwed steel pipe pile, 3 steel pipe (pile body), 3a lower pile, 3b upper pile, 4 tip wing, 5 circular steel plate, 6 joint wing, 7 taper pipe, 10 heat exchange pipe, 11 Protective cover, 12 spiral wings.

Claims (4)

A wing is attached to the tip of the steel pipe or the vicinity thereof, and has a screwed steel pipe pile that is embedded in the ground by giving a rotational force to the steel pipe, and substantially corresponds to the inclination and pitch of the wing. A steel pipe pile using geothermal heat, wherein a heat exchange pipe is spirally wound around the outer peripheral surface of the screwed steel pipe pile. A wing is attached to or near the tip of the steel pipe, and has a screwed steel pipe pile that is embedded in the ground by giving a rotational force to the steel pipe, and the outer peripheral surface of the screwed steel pipe pile has a spiral shape. A geothermal steel pipe pile characterized in that a multi-stage blade is provided and a heat exchange pipe is installed along the root of the multi-stage blade . Claim 1 Symbol placement of geothermal steel pipe, characterized in that a protective cover on the heat exchanger pipes. Geothermal steel pipe according to any one of claims 1 to 3, wherein an enlarged diameter pile head of the screw-in steel pipe pile, characterized by being wound around the heat exchange pipe to the outer peripheral surface of the enlarged diameter portion Pile.

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